pratt



Patented June 9, 1885.

ikg @q P. A. PRATT.

FRAME AND CARRIAGE FOR MACHINES. No. 319,618.

(No Model.)

[nwntar Wiinesses flitome N PETERS. Pholo-Lhhngnphor, Washinghn, n, c.

- UNITE Frames ATnN'r rricai;

FRANCIS A. PRATT, or HARTFORD, CONNECTICUT, ASSIGNOR To THE PRATT &WHITNEY COMPANY, or SAME PLACE. I

FRAME AND CARRIAGE FOR MACHINES.

.SPECIFICATION forming part of Letters Patentll'o. 319,618, dated June9, 1885.

Application filed January 30, 1885.

To aZZ whom it may concern:

Be it known that I, FRANCIS A. PRATT, a

. citizen of the United States, residing in the city and county ofHartford, State of Connectiout, have invented a new and Improved Frameand Carriage for Machines, of which the following is a specification,reference .being had to the accompanying drawings, in which- Figure 1 isa top view of apart of a machine frame and carriage embodying myimprovements. Fig. 2 is a front view of the same. Fig. 3 is an end viewdrawn in projection to Fig. 2. Figs. 4 and5are diagrams illustratingsome of the advantages resulting from my improvements.

Similar characters designate the same parts in all the figures.

This invention relates to improvements in the frame and carriage of suchmachines as lathes, milling-machines, and others of a similar class, theobject being to furnish a frame having a carriage so fitted thereon asto slide freely with the least amount of play.

The invention consists in certain combinations, which will first bedescribed in connection with the drawings, and afterward pointed out inthe claim.

In the drawings, A designates part of a lathe-bed similar to those usedfor the so called gibbed lathes. This bed consists, substantially, oftwo flanged beams, 2 and 3, set edgewise and connected by end pieces, Aand a suitable number of intermediate cross-bars, A The front side, 2,of the frame has four bearing-surfaces, as follows: top surface, E,bottom surface, 0, front surface, D, and rear surface, F, and all thesesurfaces, it will be noticed, are on the solid top flange and web of thefront beam. The rear beam, 3, has only two bearing-surfaces, H and J,corresponding, respectively, to the surfaces E and O.

B designates alathe-carriage,whichis fitted to slide on the frame. Itrests on the top surfaces, H and E, and is held down by front and rearstraps S S, which bear, respectively, on bottom surfaces, 0 and J. Thisway of bolding down such a carriage by two such straps is now Wellknown, and will be fully understood 5 but, so far as I am aware, suchcarriages have '50 not heretofore been prevented from moving (No model.)

laterally by gibbing them to one beam only of the frame-that is, thevertical bearingsurfaces have not heretofore been brought near to eachother while keeping the top surfaces, and also the bottom surfaces, wideapart. 5 5

In the frame shown in the drawings the carriage is fitted to thesurfaces D and F, which surfaces are near to each other, as shown,(surface F being between surfaces 0 J and which, being on the same solidpart, are always at a rigidlyfixed distance apart. By the usual methodof fitting the carriage it would be gibbed to surfaces D and I-one oneach beam of the frame-so that any springing together of said beams ordistortion of them 6 would directly affect the closeness of the fitting. This difficulty is entirely obviated by my improvements.

In practice a gib or shoe, as G, adjusted by screws, as 5, is providedfor regulating thegf closeness with which the carriage fits the surfacesD and F. Said gib may be placed on either of said surfaces, as may bepreferred. K designates the usual apron to which, in engine-lathes, thecarriage-feeding mechanism is attached. Since any swinging of thecarriage ina horizontal plane is prevented by the long bearing of saidcarriage on surfaces D and F, the rear part'of the carriage willgenerally require but a short bearing on surfaces H and J, asillustrated in Fig. 1. A

The bringing of surfaces D and F near to each other, as shown anddescribed, has another important advantage not involved, in simplymaking them on the same solid part of 8 5 the frame. This is illustratedby Figs. 4 and 5, in which lines M Nrepresent the horizontal distancebetween surfaces D and F in two different cases, in one of which thesaid surfaces are supposed to be about three times as wide apart as inthe other case.

P is a parallelogram having a width (vertically in the drawings) whichis less than the distance between said lines by the same amount in eachinstance. If, now, we rotate said parallelograms so as to touch bothlines, as at P, then we shall find that the angular motion will be lessin Fig. 5 than in Fig. 4; hence it is obvious the arrangement in Fig. 5is the more desirable, as it allows greater 10o play between the partswith a given rigidity I ing-surfaces O and J, and bearing-surfaces D 10of the carriage. and F, of which surfaces F has a lateral posh It willbe understood that the several surtion between surfaces 0 and J, and acarriage faces may deviate from the horizontal and verfitted to slide onsaid bearing-surfaces, sub- 5 tical planes in which they are shownwithout sfant'ally ts described.

departing from the spirit of my invention. F. A. PRATT.

Having described my invention, I claim Witnesses: The combination of amachine-frame hav- F. H. RICHARDS,

ing top bearing-surfaces, Eand H, lower bear- 0. O. PALMER.

